Blow up the balloon and then deflate it before you start. This stretches the balloon which makes it easier to fill it with the flour.
Pull the end of the balloon up over the end of a funnel.
Carefully pour flour into the funnel. Shake the funnel back and forth and tap the side of it to get the flour to go down into the balloon.
If the flour doesn’t seem to go through the funnel, use a pencil or pen to push it through.
Keep adding more and more flour to the funnel and into the balloon until you’re happy with the size.
If the balloon is running out of space to add more flour, pinch the opening of the balloon closed, then use your fingers to press down the flour in the balloon right below the funnel. Press and shape the balloon down and outwards to make space for more flour. (You'd be surprised how much flour you can fit into the balloon just by pressing it down like this!)
Remove the funnel and tie a knot in the balloon. Try to get the knot as close to the base of the balloon as you can.
Your stress ball is done!
Video
Notes
Helpful Tip: If you don’t have a funnel you can cut off the bottom of a plastic water bottle and use the opening of the bottle as your funnel.Optional: If you want, you can cut the neck off of a second balloon and stretch it over the stress ball to hide the knot in the balloon. Adding a second balloon will give your stress ball an extra layer of strength, but it will also make your stress ball more firm when you squeeze it.